Nozzle arrangement for drying and heat-treatment plants for web material



' Filed Aug. '7, 1957 July 3, 1962 A. MEIER-WINDHORST 3,041,739

NOZZLE ARRANGEME FOR 0 NG AND HEAT-TREATMENT PLA FOR MATERIAL 2 Shaets-$heat 1 INVENTOR: AUGUST MEI ER WlN DHOR ST July 3, 1962 A. MEIER-WINDHORST 3,041,739

NOZZLE ARRANGEMENT FOR DRYING AND HEAT-TREATMENT PLANTS FOR WEB MATERIAL Filed Aug. 7. 1957 2 Sheets-Sheet 2 l 1 I ,1 H, g if fi l 1 3: "I d?- INVEN 'OR AUGUST MEI ER- WINDHORST United States Patent Ofiice 3,041,739 Patented July 3, 1962 3,041,739 NOZZLE ARRANGEMENT FOR DRYING AND HEAT-TREATMENT PLANTS FOR WEB MA- TERIAL August Mcier-Windhorst, Gellertstrasse 26,

Hamburg. German Filed Aug. 7, 1957, Ser. No. 676,792 Claims priority, application Germany Dec. 15, 1956 2 Claims. (Cl. 34-156) The invention relates to a nozzle arrangement for drying and heat-treatment plants for web material wherein the web is guided without contact and in free suspension. Examples of web materials which come into question are textile fabric webs, paper webs, warp webs and the like. In these plants the heating medium is generally blown on the web from nozzles directed towards the web and led off through the spaces between the nozzles. As the pressure conditions between the nozzles, which in most casesarearranged above and below the web and facing each other, are unstable, the webs, in order to be keptsteady between the nozzles, must either be guided over rollers, laid on continuous rods or, in the case of tentering and drying frames, held in tentering chains.

As, however, it is frequently desired to feed the webs to be treated through the drying and heat-treatment plant so that they have no contract with. any guiding devices whatever and are free from tension, for example in the case of webs varnished or printed on both sides, it has been endeavoured to guide the webs so that they are in suspension or float through the plant by designing special nozzles whichare intended to produce on both sides of the web stable pressure zones by which the web is maintained in suspension or floating statebetween nozzles. Apart from the fact that these nozzles do not attain the desired effect in a satisfactory manner, these arrangements are open to the objection that the region outside the supporting cushion formed by the nozzles, that is the region in which the medium blown onto the web to be treated flows ofi therefrom, remains unstable so that, particularly in the case where the web is guided free from tension and relatively high blast speeds are used, considerable flutter ing occurs.

The arrangement according to the invention is intended to overcome this objection. As the oif-flow regions are mostly critical regions with turbulent flow, bathe elements are arranged here above and below the web to be guided, so that the medium flowing ofif along the web out of the blasting region or zones clash together. Due to this clashing, a stable pressure zone is produced on each of the two sides of the web between the two opposite bafile elements and maintains the web in free suspension between the battle elements.

This in itself enables the web to be guided free from contact and in suspension in many cases when it is not so important for the web to be guided with absolutely reliable free suspension in the region of the nozzles. In the majority of cases, however, the bafile elements in the olfflow region are combined in alternating succession with nozzles which also form stable pressure zones between themselves and the web in this region. The nozzles are then preferably constructed as double nozzles acting in and counter to the feed direction of the web.

However, experience has shown that with this free suspension guiding of the web certain disadvantages arise in connection with the drying and heating effect. This is due to the fact that the construction of the nozzles so as to obtain a perfect guiding of the web in the region where the drying medium impinges thereon, necessarily results in a reduction of the heat exchanging capacity as compared with systems in which the material to be dried is supported by mechanical means such as carrier bars, roller guides, tentering chains and the like.

It has now been found that it is also possible to eliminate this objection without thereby jeopardizing the perfeet free suspension guiding of the web by allowing the nozzles to blow onto the web to be heated or dried in the usual manner but at the same time entrusting the guiding of the web without contact and in suspension to special damming or baffle elements which serve as guiding and feeding elements not only in the region of the vertical flow but also in direct proximity to the point of impact of the vertical current from the nozzles and to the tangential off-flow, that is, baffle elements are provided not only in the oif-fiow region but also in the inflow region.

The arrangement of the battle elements in the inflow region also presents the advantage thatall nozzles of known type can be employed which, as carrying and suspension nozzles, need not be of any special design. In

the nozzle and bafile clement combination the nozzles are preferably constructed as split nozzles and extend partly or wholely in transverse direction to the material feed and v the baffle elements also extend transversely to the direction in which the material is fed. The nozzles may, however also be circular nozzles or constructed as-separate nozzles of rectangular or square cross-section. In this case the batlle element in the region of the nozzle is of annular or substantially annular shape. Correspondingly, the baflie elements in the oif-flow region may also be of annular or substantially'annular shape, in which case the individual ring bodes of the individual nozzles can be united to form exhaust bodies of certain shapes.

- Several embodiments of the invention are illustrated by way of example and diagrammatically in the accompanying drawings, in which FIG. 1 shows the arrangement of baflle elements in the ofi-flow region;

FIG. 2 shows the arrangement of baflle elements in the off-flow region in combination with double suspension nozzles;

FIG. 3 is a longitudinal section of a drying chamber with nozzle arrangement according to FIG. 2;

FIG. 4 is a cross-section on line 4-4 of FIG. 3;

FIG. 5 shows a nozzle arrangement with baflle elements intheinflow and off-flow regions; and

FIG. 6 is a fragmentary sectional view taken on line 6-6 of FIG. 3.

The arrangement illustrated in FIG. 1 shows a con- I struction in which the free suspension guiding is effected exclusively by baflle elements provided in the off-flow region. In this arrangement ordinary nozzles each having a tip portion 1, for example split nozzles, are provided above and below the web 3 While in the off-flow region which is the discharge opening intermediate adjacent nozzles bafile elements are provided which in the construction illustrated are of cylindrical shape. In the present instance, the nozzle tip portions are arranged in con: fronting pairs on opposite sides of the web 3, and the baffle elements are likewise arranged in confronting pairs between adjacent nozzles in the discharge openings. It is evident that the baffie elements 2 can also be of any other suitable shape. As indicated by the arrows in FIG. 1 a contactless, free suspension guiding system is produced for the complete guiding of the web.

In the form of construction shown in FIGS. 2 to 4 baflle elements 4 are provided in the oif-flow region in a similar manner to that shown in FIG. 1. The nozzles, however, are constructed as special nozzles in the form of double supporting nozzles 5, each having an extension projecting from the tip portion thereof substantially parallel to the direction of the web so that stable pressure zones are produced also in the inflow region in the form of supporting cushions, as indicated by the arrows. The

web 6 is thereby maintained in perfect contact-free, suspended state' while being guided, the fluttering effect being entirely eliminated.

FIGS. 3 and 4 show the whole arrangement of the construction according to FIG. 2 in a drying chamber 7. It is apparent herefrom that the nozzles 5 maintain the web 6 uniformly in suspension over its entire length and width.

In the form of construction illustrated in FIG. 5 baffle elements 8 are again arranged in the off-flow region. In the inflow region bafile elements 9, spaced from the web 31 in the present instance closer to the web than the nozzle tip portions, are provided on each side of the nozzles 10 and the nozzles are split nozzles. The arrangement operates in the following manner:

The drying medium flows from the nozzle 10 and impinges on the web 11 to be treated, in vertical direction.

Below and on both sides of the nozzle 10 baffle elements 9 are provided which arrest the tangential off-flow directly in the region of the nozzle so that a stable pressure zone forms between the opposite bafile elements 9 in the region of the tangential off-flow, which zone maintains the web to be treated free from contact between the nozzle and the baffle elements 9. These bafiie elements 9 are so constructed and arranged in relation to the nozzle 10 that a free space forms between the border surfaces of the elements 9 and the nozzle wall. This space is preferably so shaped by suitably constructing the nozzle mouth that a circular current forms around the element 9 and influences in an extremely positive manner the structure of the flow in the region of the nozzle so as to constitute a favorable heat transfer to the web to be treated.

The guide or bafile element 9 can extend so far horizontally in-the region of the nozzle stream that it forms a common exhaust passage with the corresponding element of'the neighbouring nozzle; -As, however, unstable pressure conditions would form in the region of the off-flow for the drying medium from the web to be treated, on

, both sides thereof, the battle elements 8 according to the invention are arranged at this point and divide the ofi-fiow current and also produce a stable pressure distribution in the region of this off-flow zone on both sides of the web to be treated so that it is smoothly guided without contact and in free suspension.

I claim:

1. In apparatus for treating elongated web material, means for freely suspending the web material comprising a plurality of nozzles each having a tip portion terminating adjacent the web, said tip portions being arranged in a row of confronting pairs on opposite sides of said web material, means supplying gaseous treating medium to said nozzles, means defining discharge openings between adjacent nozzles on each side of the web material, and a series of baffle elements arranged in a row of confronting pairs in said discharge openings and spaced closer to said web material than said nozzle tip portions, said nozzle tip portions, bafile elements and discharge openings providing flow of said treating medium operable to support the web in a stable state of free suspension and effect substantially uniform treating of said web material.

2. In apparatus for treating elongated web material, means for freely suspending the web material therein comprising a plurality of nozzles at opposite sides of the web material each having a tip portion terminating adjacent to the web, means supplying gaseous treating medium to said nozzles, means defining discharge openings between adjacent nozzles at each side of the web material, and guide elements at respectively opposite sides of the web material disposed adjacent said nozzle tip portions and spaced from said nozzle tip portions and said web material to provide a continuous passageway between the nozzle tip portions and the discharge openings affording fiow of said treating medium therebetween, said guide elements extending the entire width of the web material between adjacent nozzles and each including a surface parallel to the web spaced closer thereto than said nozzle tip portions, said nozzle tip portions, guide elements and discharge openings providing flow of said treating medium operable to support the web in a stable state of free suspension and effect substantially uniform treating of said web material.

References Cited in the file of this patent UNITED STATES PATENTS 2,144,919 Gautreau Jan. 24, 1939 2,492,974 Dungler Ian.-3, 1950 2,591,621 Shegda Apr. 1, 1952 2,682,116 Dungler June 29, 1954 

